During all types of joint replacement surgery, and in many other surgical procedures, it is necessary to make specific cuts or to drill holes into specific areas of bone. Both the point and angle of entry of the cut or drill hole is important. This is particularly so in the case, for example, of femoral head resurfacing, where it is necessary to drill a pilot hole that passes through the centre of the femoral neck at a specific angle with respect both to the epicondylar axis and the femoral shaft axis. Guide tools exist to aid surgeons in the placement of bone cuts and guide holes. Such tools are often difficult and time consuming to operate, and are inaccurate. Many of the tools of the prior art are also bulky, requiring the removal or displacement of large areas of soft tissue in order to be used.
Use of conventional tool guides generally involves at least the steps of attaching the guide, referencing the position of the guide from an anatomical feature, and adjusting the position of the guide to correspond to the optimal position indicated in the referencing step. Several iterations of referencing and adjustment may be required to achieve the correct position and orientation of the guide.